Airway adapters are generally used with patients being given respiratory assistance, such as patients under anesthesia, or patients on life support systems, to connect between the patient airway (mouth, nose, tracheal tube) and a ventilating tube of a breathing apparatus. The ventilating tubes convey breathing gases to the patient and exhaled breath away from the patient (typically, the airway adapter is in the form of a short connector of tubular shape making a connection between the generally different cross sections of tubes).
End-tidal carbon dioxide (ETCO2) detection provides a non-invasive indication of the proper insertion of the airway tube is obtained by the analysis of the exhaled breath gases. End-tidal carbon dioxide (ETCO2) detection indicates to the clinician whether the airway tube is inserted correctly into the trachea. If inserted correctly, carbon dioxide is detected. If the airway tube is inserted incorrectly (into the esophagus), no carbon dioxide is detected and the clinician knows to remove the airway tube and reinsert it.
Airway components are typically made as plastic injection moldings, keeping production costs low. The amount of void volume (also known as dead space) in such airway components is typically very considerable. For neonatal applications, especially those with low birth weight, the patient has very little exhalation air volume. Airway adapters needs to have minimal added void volume to reduce the effects of gas mixing which would adversely affect the integrity of a calorimetric carbon dioxide detector membrane. Existing devices claim to have 3 mL of internal volume (dead space), when in actuality, these devices have 5 mL of internal volume before they are inserted into a circuit and 3 mL of internal volume after inserted into a circuit.
There exists a serious need for a sampling airway adapter for use with low birth weight neonatal patients, which overcomes the disadvantages of available adapters by reducing the internal volume to approximately 1 mL when inserted into a circuit and used with neonatal patients.